Police say eight Philadelphia high school students waiting to board a city bus after classes Wednesday were wounded by gunshots from suspects who jumped from a car and opened fire, the fourth shooting on the transit system in as many days.

The previous three shootings each involved a fatality. At least one student was critically wounded at the bus stop, a 16-year-old who was hit nine times, Kevin Bethel, the city’s police commissioner, said at a news conference. The others were in stable condition.

Bethel said the Northeast High School students, ranging in age from 15 to 17, were waiting for the bus around 3 p.m. when three people emerged from the car, which was waiting at the scene, and fired more than 30 shots.Police then received numerous 911 calls about a “mass shooting on the highway near Dunkin’ Donuts,” in northeast Philadelphia, according to police spokesperson Tanya Little.